diff -r 69aa17b1f894 Lib/subprocess.py
--- a/Lib/subprocess.py	Wed Jan 13 07:48:57 2016 -0800
+++ b/Lib/subprocess.py	Wed Jan 13 17:30:51 2016 +0100
@@ -520,6 +520,16 @@ DEVNULL = -3
 # but it's here so that it can be imported when Python is compiled without
 # threads.
 
+def _optim_args_from_interpreter_flags():
+    """Return a list of command-line arguments reproducing the current
+    optimization settings in sys.flags."""
+    args = []
+    value = sys.flags.optimize
+    if value > 0:
+        args.append('-' + 'O' * value)
+    return args
+
+
 def _args_from_interpreter_flags():
     """Return a list of command-line arguments reproducing the current
     settings in sys.flags and sys.warnoptions."""
@@ -527,7 +537,6 @@ def _args_from_interpreter_flags():
         'debug': 'd',
         # 'inspect': 'i',
         # 'interactive': 'i',
-        'optimize': 'O',
         'dont_write_bytecode': 'B',
         'no_user_site': 's',
         'no_site': 'S',
@@ -535,6 +544,7 @@ def _args_from_interpreter_flags():
         'verbose': 'v',
         'bytes_warning': 'b',
         'quiet': 'q',
+        # -O is handled in _optim_args_from_interpreter_flags()
     }
     args = []
     for flag, opt in flag_opt_map.items():
diff -r 69aa17b1f894 Lib/test/support/__init__.py
--- a/Lib/test/support/__init__.py	Wed Jan 13 07:48:57 2016 -0800
+++ b/Lib/test/support/__init__.py	Wed Jan 13 17:30:51 2016 +0100
@@ -2053,6 +2053,11 @@ def args_from_interpreter_flags():
     settings in sys.flags and sys.warnoptions."""
     return subprocess._args_from_interpreter_flags()
 
+def optim_args_from_interpreter_flags():
+    """Return a list of command-line arguments reproducing the current
+    optimization settings in sys.flags."""
+    return subprocess._optim_args_from_interpreter_flags()
+
 #============================================================
 # Support for assertions about logging.
 #============================================================
diff -r 69aa17b1f894 Lib/test/test_compileall.py
--- a/Lib/test/test_compileall.py	Wed Jan 13 07:48:57 2016 -0800
+++ b/Lib/test/test_compileall.py	Wed Jan 13 17:30:51 2016 +0100
@@ -219,9 +219,8 @@ class CommandLineTests(unittest.TestCase
             raise unittest.SkipTest('not all entries on sys.path are writable')
 
     def _get_run_args(self, args):
-        interp_args = ['-S']
-        if sys.flags.optimize:
-            interp_args.append({1 : '-O', 2 : '-OO'}[sys.flags.optimize])
+        interp_args = support.optim_args_from_interpreter_flags()
+        interp_args.append('-S')
         return interp_args + ['-m', 'compileall'] + list(args)
 
     def assertRunOK(self, *args, **env_vars):
diff -r 69aa17b1f894 Lib/test/test_inspect.py
--- a/Lib/test/test_inspect.py	Wed Jan 13 07:48:57 2016 -0800
+++ b/Lib/test/test_inspect.py	Wed Jan 13 17:30:51 2016 +0100
@@ -30,6 +30,7 @@ from test.support import MISSING_C_DOCST
 from test.support.script_helper import assert_python_ok, assert_python_failure
 from test import inspect_fodder as mod
 from test import inspect_fodder2 as mod2
+from test import support
 
 from test.test_import import _ready_to_import
 
@@ -3536,14 +3537,14 @@ class TestMain(unittest.TestCase):
 
     def test_details(self):
         module = importlib.import_module('unittest')
-        rc, out, err = assert_python_ok('-m', 'inspect',
+        args = support.optim_args_from_interpreter_flags()
+        rc, out, err = assert_python_ok(*args, '-m', 'inspect',
                                         'unittest', '--details')
         output = out.decode()
         # Just a quick sanity check on the output
         self.assertIn(module.__name__, output)
         self.assertIn(module.__file__, output)
-        if not sys.flags.optimize:
-            self.assertIn(module.__cached__, output)
+        self.assertIn(module.__cached__, output)
         self.assertEqual(err, b'')